Improvement in pneumatic drills



UNITED STATES @Partant @Frictia STUART GWYNN, 0F NEWT YORK, N. Y.

IMPROVEMENT IN PNEUMATIC DPtILLS.

Speciflcation forming part of Letters Patent N0. 44,722, dated October18, 1864.

10 @Z5 whom t may concern:

Beit known that I, STUARTIGWYNN, of New York, in the county and Sta-teof New York, haveinven ted certain new and useful Improvements inPneumatic Drills; and I hereby declare that the following is a full,clear, and exact description of the same, reference being' had to theaccompanying drawings, in which- Figure l is a plan view of an apparatusconstructed in accordance with this my invention, and Fig. 2 is asectional elevation of the same according to line x y in Fig. l.

i In pneumatic drills as heretofore constructed the drill-bar or tool isrigidly ,connected with the piston or piston-rod of the pneumatic orsteam engine, which is arranged to operate the drill-bar in the mannerof achurn, and they are therefore denominated churn-drills. Thisarrangement has been found in many instances and under certaincircumstances to be inconvenient and the source of loss of power.

To obviate these and other objections is the object of this invention;and it consists in the arrangement and construction of a pneumaticdrill, in which the drill-bar is allowed to remain in contact withtherock to be bored, and in which the steam or pneumatic action is such asto impart its force to the drill-bar in the fashion of a sledge-hammerwhen striking a cutting-tool. These drills I therefored denominatesledge-drills.

To enable others to make and use this my invention, I shall now proceedto describe the construction and operation of a drill made in accordancewith this invention and-to be operated by steam.

Ais the steam-cylinder,or cylinder arranged to be worked by compresssedair or other elastic fluid. It is composed of a flanged cylinder, havingon one side a steamor valve chest with ports for the passage of steam orair to and from the cylinder. The port B starts in the chest at the rearend thereof and terminates in the cylinder at its forward end. The portC, on the other hand, starts in the chest at the forward end andterminates in the cylinder at the rear end. The two ports7 it will beseen, are situated in two different vertical planes and cross eachother, the exhaustchamber D being arranged between them. The valve E,which is of the cup kind, is operated from without by means of tappetsor stops G G, fast on the valve-rod F. Through the cylinder passes ahollow piston-rod, I, traversing' suitable stuffing-boxes, H, intheheads of the cylinder. Upon thishollowpistonrod is mounted the piston Jof ordinary or suitable construction, both the piston and rod beingrigidly connected and move in unison when actuated by the power ofsteam. The drill-bar K, which may be inserted into the socket of atool-holder,`is arranged within the hollow piston rod to freely andloosely play therein. The drill-bar or its holder is enlarged, so as topresent a shoulder at L, against which the surrounding screw M, withwhich the piston-rod is connected,abuts. The drill-bar is prevented fromrotating within the hollow screw M by means of feathers NN, fitting thelongitudinal groove O, wrought in the drillbar. This male screw issecured in a female screw-nut, P, which in its turn is securedjto thepiston-rod I by means of reversible attachment, consisting of an upperand lower flan ge on the nut, indented in conformity with projections onthe piston-rod, the whole constituting a sort of bayonet-catch. To thepiston-rod is further attached an arm or lever, through an orifice ofwhich passes the valve-rod, as before described. This lever slides alongthe valverod until it comes in contact at either end or its stroke withthe fixed stops G G', which causes the shifting of the valve at properintervals of time for the reversal of the movement and power. Sidestandards may be applied to thisv drill in the same manner as I havedescribed in an application of even date herewith. To such standards maybe attached an inclined plane, cam, or other equivalent device, withwhich is engaged a spring-clutch, by means of a tail-piece, R, whichcauses the clutch when rotated in one direction rmly to grasp the screwand to release its hold upon it when turned in the opposite direction.By this means the screw is advanced automatically within the hollowpiston-rod as the work progresses, and the screw by which the blow isgiven to the sledge drill follows up the drill as it penetrates therock.

Having thus described my invention and the manner in which the same isor may be performed, I claiml. Amachine for boring rocks, Src., operatedby steam, air, or other elastic fluid, consisting of a cylinder, piston,hollow piston-rod, and

their appurtances, rendering the same self-act- A ing under such anarran gement as that the blow shall be exerted upon a drill-bar or itsholder loosely inserted into the hollow piston-rod, allowing the drillto remain in Contact with the rock, substantially as hereinbeforedescribed.

2. In pneumatic rock-drills, operating as described, the combination ofa loose drill-rod and hammer with an automatic screw-feeding device7 soas to follow up the drill as the work progresses, substantially asherein set forth.

3. The method of securing the liollowscrew to the hollow pistonrod bymeans of a reversible nut, constructed and operating in the manner andfor the purposes Set forth.

In testimony whereof I have signed my name to this specification beforetwo subscribing witnesses.

STUART GWYNN. Witnesses:

EDM. F. BROWN, Jos. L. GooMBs.

